Electrospray ionization of neutral metal dithiocarbamate complexes using in-source oxidation

Schoener, Dale; Olsen, Mark A.; Cummings, Paul; Basic, Cecilia

doi:10.1002/(sici)1096-9888(199910)34:10<1069::aid-jms868>3.0.co;2-q

Cited by 22 publications

(20 citation statements)

References 38 publications

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“…The ionization of Cu(II) dibutyl dithiocarbamate in the ESI source involves simple oxidation of Cu(II) to Cu(III) [14,21]. Such behavior is not unusual for transitionmetal dithiocarbamates of the type M(R 2 dtc) 2 for which the high oxidation state complexes [M(R 2 dtc) 2 ] ϩ are remarkably stable [20].…”

Section: Resultsmentioning

confidence: 98%

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Enhanced desorption ionization using oxidizing electrosprays

Nefliu

Cooks

Moore³

2006

J. Am. Soc. Mass Spectrom.

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A signal enhancement of two orders of magnitude was achieved when reactive desorption electrospray ionization (DESI) was used to investigate copper(II) dibutyl dithiocarbamate, Cu(II)(bu 2 dtc) 2 , found in a specialized polymer. Cu(II) was oxidized to Cu(III) during the DESI experiment by oxidants in the spray solvent. Such oxidants could be present or formed during electrospray (e.g., O 2 ) or deliberately added to the spray solvent (this approach is called reactive DESI). When a strong oxidizing agent (e.g., iodine) was added to the spray solvent, the signal increased by two orders of magnitude relative to the pure solvent spray. The correlation between the standard reduction potential of the oxidant and the signal intensity and signal to noise ratio of the product ion for various reagents, was tested and discussed. The observed DESI enhancements in rates of oxidation are not observed in homogeneous solution. The major peaks in the collision induced dissociation (CID) . DESI is a heterogeneous process involving charged solution-phase droplets interacting with a condensed phase sample to yield gas-phase ions. It is therefore straightforward to add solution-phase reagents to the spray solvent to mediate the interfacial chemistry. This capability, sometimes called reactive DESI, has been used to perform selective ligand/protein binding [1], to stereoselectively generate covalent cyclic boronates from 1,2-diols [11] and to perform Eberlin transacetalization of acylium ions (Eberlin, M. N., unpublished results). These instances emphasize the analogy between DESI and chemical ionization (CI), even though the former employs solution-phase rather than gas-phase reagents as is done in the conventional CI experiment.We demonstrate in this paper that redox reactions can be used to advantage in DESI analysis (as they have previously been so used in electrospray ionization [12,13]). We report a very large enhancement in the efficiency of ionization of a particular metal complex present in a specialized layered ethylene/propylene/ diene polymer [14] by using redox spray reagents to assist in ionization. The analyte investigated is the neutral copper(II) dibutyl dithiocarbamate complex, Cu(II)(bu 2 dtc) 2 , which is ionized to [Cu(III)(bu 2 dtc) 2 ] ϩ (m/z 471) during the DESI experiment (eq 1). Electrochemical processes accompanying electrospray ionization (ESI) were first recognized by Kebarle et al. [12] and thoroughly investigated by Van Berkel and co-

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Section: Resultsmentioning

confidence: 98%

“…Metal complexes with dithiocarbamates have been previously investigated by ESI-MS and the observed fragments identified [14,21]. We attempted to elucidate the fragmentation pattern of the complex [Cu(III)(bu 2 dtc) 2 ] ϩ to confirm the reported results and to identify new fragments.…”

Section: Resultsmentioning

confidence: 99%

Enhanced desorption ionization using oxidizing electrosprays

Nefliu

Cooks

Moore³

2006

J. Am. Soc. Mass Spectrom.

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“…The fragmentation behavior of some metal complexes with nitrogen-and oxygen-based donor ligands was previously reported [13]. It can be noted that, to date, surprisingly little is known about the mass spectral behavior of the dithiocarbamate complexes [14][15][16].In our studies of mass spectra we found an interesting possibility of detecting a fragmentation pattern for the series of complex compounds [17,18]. This paper is an extension of the study of copper(II) complexes with octaazamacrocyclic ligand tpmc and heterocyclic dithiocarbamate ligands [7], i.e., piperidine-(Pipdtc), 4-morpholine-(Morphdtc), 4-thiomorpholine-(Timdtc), piperazine-(Pzdtc), or N-methylpiperazine (N-Mepzdtc) dithiocarbamates, respectively ( Fig.…”

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confidence: 89%

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confidence: 99%

Mechanism of mass spectral fragmentation of dinuclear copper(ii) complexes with heterocyclic dithiocarbamates and octaazamacrocyclic ligand

Sovilj

Babić‐Samardžija

Avramović³

2005

J Appl Spectrosc

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has been investigated. The results were shown to be of mechanistic significance, clarifying the major products of their fragmentation. A possible mechanism entails a multi-step decomposition process that can be separated into individual steps depending on their molecular structures. Every step is determined to some extent by the nature of the intermediates.Introduction. Dithiocarbamate ligands have high tendency for MS 4 and MS 6 coordination and act as almost uninegative bidentate ligands coordinating through the sulfur atoms [1]. Both four-and hexa-coordinated dithiocarbamate complexes with transition metal ions have been the subject of many studies [2,3]. However, being very stable towards substitution, relatively little is known about their mixed-ligand complexes. Such species could be achieved with other ligands of comparable coordinating ability. In that respect, macrocyclic N,N′,N′′,N′′′-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc), as a powerful octadentate ligand, is especially suitable for attaining in boat coordination mode [4-8] stable dinuclear metal(II) complexes with an additional exocyclic ligand. As a consequence, dithiocarbamate ligand forms a bridge between the two metal atoms [7].In the last few years, mass spectrometry has been an extremely powerful tool concerned with structure identification and determination [9][10][11][12]. Analyzing metal-coordinated organic ligands introduces new features in the fragmentation patterns [9,10]. Mass spectral studies of metal complexes are considerably simplified mainly because of the low volatility of the complexes. The fragmentation behavior of some metal complexes with nitrogen-and oxygen-based donor ligands was previously reported [13]. It can be noted that, to date, surprisingly little is known about the mass spectral behavior of the dithiocarbamate complexes [14][15][16].In our studies of mass spectra we found an interesting possibility of detecting a fragmentation pattern for the series of complex compounds [17,18]. This paper is an extension of the study of copper(II) complexes with octaazamacrocyclic ligand tpmc and heterocyclic dithiocarbamate ligands [7], i.e., piperidine-(Pipdtc), 4-morpholine-(Morphdtc), 4-thiomorpholine-(Timdtc), piperazine-(Pzdtc), or N-methylpiperazine (N-Mepzdtc) dithiocarbamates, respectively ( Fig. 1), which prompted us to clarify the detailed mechanism of their mass spectral behavior. The aim of these investigations is the ability to predict and hence to interpret principal modes of mass spectral fragmentation of fairly complicated mixed-ligand complexes [7,8,[17][18][19] and, hopefully, to develop a parallel route to analogues.

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“…They demonstrated that higher flow rates resulted in reduced populations for the higher charge states. Eight substituted tris(dithiocarbamato)iron(III) complexes were oxidized in-source by Basic et al [45].…”

Section: Redox Reactions In the Electrospray Ionization Interfacementioning

confidence: 99%

On-line electrochemistry – MS and related techniques

Diehl

Kärst

2002

Anal Bioanal Chem

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This review summarizes publications on the on-line coupling of electrochemistry with mass spectrometry. After a brief historic introduction it is divided into three parts, organized in order of increasing complexity of the experimental arrangement. The first section deals with the use of the electrospray ion source as an electrochemical reactor for oxidation or reduction reactions. It is followed by the second part which covers the hyphenation of different kinds of electrochemical flow cell with a variety of ionization interfaces. The last section focuses on the on-line coupling of chromatographic techniques with electrochemical flow cells and mass spectrometry.

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Electrospray ionization of neutral metal dithiocarbamate complexes using in-source oxidation

Cited by 22 publications

References 38 publications

Enhanced desorption ionization using oxidizing electrosprays

Enhanced desorption ionization using oxidizing electrosprays

Mechanism of mass spectral fragmentation of dinuclear copper(ii) complexes with heterocyclic dithiocarbamates and octaazamacrocyclic ligand

On-line electrochemistry – MS and related techniques

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